Printing machine



C. F. FAWDRY April 17, 1934 PRINTING MACHINE Filed June 16 1932 2Sheets-Sheet l April 1934- c. F. FAWDRY Filed June 16, 1932 FatenteclApr. 17, 1934 UNITED STATES PATENT OFFICE Application June 16, 1932,Serial No. 617,623 In Great Britain July 17, 1931 Claims.

The present invention concerns improvements in or relating to printingmachines in which the printing cylinder comprises a thin sheet of metalcarrying the printing surface wrapped round a a drum of the type whichis divided longitudinally into a plurality of sections.

Usually, rotary reel-fed photogravure machines employ printing cylindersin which the printing surface is formed upon the outer surface of acomparatively thick copper sleeve which is mounted upon a steel drumcarried by or formed on a steel shaft. These sleeves are very expensiveto prepare. It is recognized that if the surface of a thin metal sheet(or design plate as it is frequently termed) wrapped round a drum couldbe employed as the printing surface considerable advantages wouldresult. Various attempts have been made to obtain these advantages, butdifficulties have been encountered due to the difliculty of tensioningthe thin design plate and holding it properly tensioned and trulycylindrical during use.

Objects of the present invention are to provide for the rapid tensioningof such a thin plate, to 5 provide for the plate remaining properlytensioned and cylindrical even after considerable use, and to provideplate supporting and tensioning means which shall be comparatively easyand cheap to construct and maintain.

The invention will become apparent to those skilled in the art from thefollowing description in conjunction with the accompanying diagrammaticdrawings, of one-illustrative construction according to the invention.

' In the drawings,

Fig. 1 is a cross-sectional end elevation of one illustrative drum witha design plate in place;

Fig. 2 is an end elevation similar to Fig. 1, with the lifting gear inplace and the drum opened;

Fig. 3 is a front elevation, partly in section, of part of the drum ofFig. 1; and

; Fig.4 is a detail in perspective showing the means for holding thedesign plate in place on the drum.

The-construction about to be described includes a printing cylinderindicated generally at 1 (Fig.

3) that comprises a steel drum indicated geneially at 3 carried by thecylinder shaft 5 and a thin sheet of copper 7 (design plate)- which iswrapped round the drum 3 and'which carries theetche'd printing surface.The drum 3- is divided diametrically (along a horizontal diameterasindicated in Fig. 1) into two sections, an i upper'section-lland alower section 13. The

lower section 13 is, in this particular instance, formed integrally withthe shaft 5. Considering Fig. 1 there is projecting upwardl from themiddle portion of the top surface of the lower section 13 a hump 15 thatextends along the whole length of the section. The left hand side (asviewed in Fig. 1) of the hump is vertical at 1'7 but has its top cornerrounded oif at 19. to meet the horizontal top surface 21 of the hump.Immediately to the left of the hump there is, in the top surface of thelower section 13, a rectangular notch 23, the right hand side 25 ofwhich is in vertical alignment with the left hand side 1'7 of the hump.This notch extends along the whole length of the drum. The right handside 27 of the hump slopes downwardly and outwardly so that the hump iswidest at its base. About midway between the right hand base of the hump15 and the right hand edge of the section 13 there is a rectangularrecess 29 which extends along the whole length of the section and inwhich is fixed, by means of screws, a plate 31 that carries at intervalsof about four inches a number of hooks 33 pointing inwardly. Near theright hand top corner of the hump 15 is a row of brackets 35 cast withthe hump, each bracket having a similar hook 37 pointing upwardly;alternatively there might be a plate similar t plate 31.

The upper section 11 of the drum has its middle portion cut away to forma hollow 41 for the reception of the hump 15. The base 43 of the hollow41 is adapted, when the two sections are closed firmly together, to restupon the horizontal top surface 21 of the hump. The part 45 of thesection 11 adjacent to the part 19 of the hump is cut away sothat itdoes not contact with the hump. The left hand margin 47 of the hollowadjacent to the vertical side 17 of the hump is vertical. Projectingdownwardly from the lower left hand face of the upper section 11 is arib 51 having a vertical left hand margin 52; the right hand margin 53of the rib is slightly backed'off so as not to contact with the righthand margin 25 of the notch 23. The arrangement is such that the lefthand margin 52 of the rib and the left hand vertical face 4'7 of thehollow 41 will by contact with the adjacent surfaces of the low-- ersection 13 locate the two sections relatively to one another in ahorizontal diametrical direc-' tion; the base 43 of the hollow 41 andthe top 21 of the hump position the two sections relatively on avertical diameter. Thus when the sections are together they will form acylindrical drum. The lower face 55 (Fig. 2) of the upper section 11' tothe right of the hollow ll and the adjacent upper face 57 of the lowersection 13 to the right of the hook-receiving recess 29 are cut awaysomewhat to permit of the insertion of the design plate 7; the lowersection 13 may have projections as 59 (Fig. 2) to act as bearing facesfor the two sections when the two sections are closed.

The parts are assembled as follows:-

The design plate '7, the upper section 11 being raised about an axisoutside its left. hand edge, is wrapped round the drum. The lower marginof the sheet '7 is hooked on to the hooks 33 in the recess 29 by meansof a rod 61 (Fig. 4) attached to the said margin; the upper margin ofthe sheet '7 is similarly hooked on to the hooks 37 on the hump, seeFig. 2. The upper section 11 is then lowered to close upon the lowersection 13 and in doing so it stretches the design plate tightly roundthe drum in correct position for printing, see Fig. 1. The adjacent lefthand corners 63 and 65 of the two sections are then in contact so thatthere is no gap or depression in the drum surface at that locationbetween the sections. In consequence no depression will be formed at thecorresponding location in the design plate '7 by the impression cylinderduring printing. A piece of leather 66 is placed between the sections 11and 13 and is afterwards smoothed with a hot iron so that it forms acontinuation of the sections such that the doctor can ride over thejunction between the sections readily.

In order to force and hold the two sections 11 and 13 of the drumtogether each end of the drum is provided with the following devicez-Theend of each section has formed on it an axiallyprojecting boss as '71(Fig. 3) the adjacent bosses forming together a single boss in the formof a truncated cone with its smaller diameter at the end remote fromthe'drum. The adjacent portion of the shaft 5 is screwed at '73 and isprovided with a heavy nut having an inwardly-projecting annulus '77.This annulus '77 is provided externally with a light nut '79 betweenwhich and the adjacent face of the heavy nut 75 is formed a recess 81;in this recess 81 lies loosely a flange 83 that projects towards theaxis of the shaft 5 from a ring 85 the inner surface of which is conedto correspond to the shape of the coned boss 71. The arrangement is suchthat when the upper section 11 of the drum is positioned on the lowersection 13, the coned ring 85 is forced by means of the large nut 75 onto the coned boss 71 so as to force the two sections of the drum closelytogether. By rotation of the large nut '75 in the reverse direction theconed ring 85 will (through the light nut '79) be positively drawn offthe coned boss '71 to release the sections.

The jig or hinge device for opening the sections of the drum will now bedescribed; this device is in two parts, one part for attachment to eachend of the drum, and consequently it will be necessary to describe thepart at one end only. Two arcuate bands 91 and 93 (Fig. 2) are providedwhich, when the coned ring 85 is withdrawn from the boss 71, areattached by means of setscrews 95 (having knurled heads so that they canreadily be manipulated by hand) to the end of the adjacent section andare tapered to fit on the coned boss 71, one band being attached to eachof the drum sections. The left-hand ends of the bands 91, 93 (adjacentto the rib 51 and notch 23) are bent outwardly from the drum axis andare provided with over-lapping apertured bosses as 97 which are hingedtogether by means of a hinge pin 99; the axis of the hinge pin isparallel or approximately parallel with the axis of the drum and lies inline with the horizontal diameter of the drum along which the sectionaldivision of the drum occurs. The other end of the band 91 has anoutwardly-projecting extension 101 which when the drum is closed liesapproximately parallel with the diameter of drum division. The outer endof this extension has one end of a chain or a link 103 connected to it,the other end of which is provided with a hook which is adapted to hookover a projection extending from the bearing of the impression cylindershaft. This bearing, as is usual, is mounted in up-and-down guide waysso that it can be moved towards and from the printing cylinder as iscustomary. The arrangement is such that when it is desired to open theprinting drum for the attachment or removal of a design plate, the hingedevice 91, 93 is attached to the sections of the drum at each end, thehook is hooked on to the projection of the impression cylinder bearing,and the impression cylinder is moved away from the printing cylinder inusual manner. As a result the upper section of the printing drum isrotated about the axis of the hinge so as to raise the said section andremove tension from the design plate as in Fig. 2 so that the margin ofthe latter can be unhooked and the design plate removed. By the use ofsuch a hinge the jointing faces may be opened by pivoting but the saidfaces may yet fall upon a radius of the drum so as to give the strongestedges possible; as the axis of movement is outside the drum these edgesare not in contact during opening and so are not liable to be brokenoff.

It will be appreciated that by reason of the foregoing construction abase for the design plate is obtained which is cylindrical except at thelocation where the margins of the design plate pass inwardly into theinterior of the drum for attachment; the joint (at 63, 65) between thesections on the opposite side of the drum is completely closed so thatno longitudinal depression in the design plate is formed by theimpression cylinder at that location. Consequently the design plate canbe used as a continuous printing surface all around the cylinder exceptat the attaching location mentioned.

It is to be observed that the amount of slack produced in the designplate '7 for a given opening of the section 11 (restricted in practiceby the limited amount by which the superposed impression cylinder can belifted) is about twice that obtained with known arrangements in whichthe ends of the plate are anchored to different sections of thecylinder. This additional slack facilitates the lifting of the plate offthe somewhat inaccessible anchoring hooks without bending said platesharply and so risking damage'to its printing surface.

What I claim is:

1. Printing cylinder, comprising two separable complementary sectionswhich together form a cylindrical drum, a flexible design plate Wrappedaround said drum, anchoring means attaching both margins of said designplate to one and the same section of said drum and means for secur ingsaid sections together in drum form with the design plate tensionedaround the same.

2. Printing cylinder, comprising a drum divided longitudinally into twosections separable by a rotary movement of one section in relation tothe other about an axis to one side of said drum, the line of divisionat the cylinder surface on that side of the drum being substantiallyradial so that the sections fit together at said surface without gap andwithout sharp angles, a flexible design plate wrapped around said drum,anchoring means attaching both margins of said design plate to one andthe same section of said drum, and means for securing said sectionstogether in drum form with the design plate tensioned around the same.

3. Printing cylinder, comprising two separable complementary sectionswhich together form a cylindrical drum, a flexible design plate wrappedaround said drum, anchoring means attaching both margins of said designplate to one and the same section of said drum, and means for securingsaid sections together in drum form with the design plate tensionedaround the same, said securing means consisting, at each end of thedrum, of an externally coned boss on the drum-sections, an internallyconed and flanged ring engageable over said boss to draw the drumsections together, and a nut provided with flanges located one on eitherside of the ring-flange and thereby adapted both for engaging said ringover said boss and for disengaging said ring from said boss.

4. Printing cylinder comprising a drum divided longitudinally into twosections separable by a rotary movement of one section in relation tothe other about an axis located outside of said drum, a flexible designplate wrapped around said drum, anchoring means attaching both marginsof said design plate to one and the same section of said drum, and meansfor securing said sections together in drum form with the design platetensioned around the same.

5. Printing cylinder comprising a drum divided longitudinally into twosections separable by 1'0!- tation of one section relatively to theother section, a flexible design plate wrapped around said drum,anchoring means attaching both margins of said design plate to saidother drum section and a hinge device for said drum sections having itsaxis outside said drum, by means of which device said one drum sectioncan be rotated in relation to the other for tensioning and releasing thedesign plate.

CHARLES FREDERICK FAWDRY.

